// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_CONTROLS_LABEL_H_
#define UI_VIEWS_CONTROLS_LABEL_H_

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "ui/gfx/render_text.h"
#include "ui/views/view.h"

namespace views {

// A view subclass that can display a string.
class VIEWS_EXPORT Label : public View {
public:
    // Internal class name.
    static const char kViewClassName[];

    // The padding for the focus border when rendering focused text.
    static const int kFocusBorderPadding;

    Label();
    explicit Label(const base::string16& text);
    Label(const base::string16& text, const gfx::FontList& font_list);
    ~Label() override;

    // Gets or sets the fonts used by this label.
    const gfx::FontList& font_list() const { return render_text_->font_list(); }

    virtual void SetFontList(const gfx::FontList& font_list);

    // Get or set the label text.
    const base::string16& text() const { return render_text_->text(); }
    virtual void SetText(const base::string16& text);

    // Enables or disables auto-color-readability (enabled by default).  If this
    // is enabled, then calls to set any foreground or background color will
    // trigger an automatic mapper that uses color_utils::GetReadableColor() to
    // ensure that the foreground colors are readable over the background color.
    void SetAutoColorReadabilityEnabled(bool enabled);

    // Sets the color.  This will automatically force the color to be readable
    // over the current background color, if auto color readability is enabled.
    virtual void SetEnabledColor(SkColor color);
    void SetDisabledColor(SkColor color);

    SkColor enabled_color() const { return actual_enabled_color_; }

    // Sets the background color.  This won't be explicitly drawn, but the label
    // will force the text color to be readable over it.
    void SetBackgroundColor(SkColor color);
    SkColor background_color() const { return background_color_; }

    // Set drop shadows underneath the text.
    void SetShadows(const gfx::ShadowValues& shadows);
    const gfx::ShadowValues& shadows() const { return render_text_->shadows(); }

    // Sets whether subpixel rendering is used; the default is true, but this
    // feature also requires an opaque background color.
    // TODO(mukai): rename this as SetSubpixelRenderingSuppressed() to keep the
    // consistency with RenderText field name.
    void SetSubpixelRenderingEnabled(bool subpixel_rendering_enabled);

    // Sets the horizontal alignment; the argument value is mirrored in RTL UI.
    void SetHorizontalAlignment(gfx::HorizontalAlignment alignment);
    gfx::HorizontalAlignment horizontal_alignment() const
    {
        return render_text_->horizontal_alignment();
    }

    // Get or set the distance in pixels between baselines of multi-line text.
    // Default is 0, indicating the distance between lines should be the standard
    // one for the label's text, font list, and platform.
    int line_height() const { return render_text_->min_line_height(); }
    void SetLineHeight(int height);

    // Get or set if the label text can wrap on multiple lines; default is false.
    bool multi_line() const { return multi_line_; }
    void SetMultiLine(bool multi_line);

    // Get or set if the label text should be obscured before rendering (e.g.
    // should "Password!" display as "*********"); default is false.
    bool obscured() const { return render_text_->obscured(); }
    void SetObscured(bool obscured);

    // Sets whether multi-line text can wrap mid-word; the default is false.
    // TODO(mukai): allow specifying WordWrapBehavior.
    void SetAllowCharacterBreak(bool allow_character_break);

    // Sets the eliding or fading behavior, applied as necessary. The default is
    // to elide at the end. Eliding is not well-supported for multi-line labels.
    void SetElideBehavior(gfx::ElideBehavior elide_behavior);
    gfx::ElideBehavior elide_behavior() const { return elide_behavior_; }

    // Sets the tooltip text.  Default behavior for a label (single-line) is to
    // show the full text if it is wider than its bounds.  Calling this overrides
    // the default behavior and lets you set a custom tooltip.  To revert to
    // default behavior, call this with an empty string.
    void SetTooltipText(const base::string16& tooltip_text);

    // Get or set whether this label can act as a tooltip handler; the default is
    // true.  Set to false whenever an ancestor view should handle tooltips
    // instead.
    bool handles_tooltips() const { return handles_tooltips_; }
    void SetHandlesTooltips(bool enabled);

    // Resizes the label so its width is set to the width of the longest line and
    // its height deduced accordingly.
    // This is only intended for multi-line labels and is useful when the label's
    // text contains several lines separated with \n.
    // |max_width| is the maximum width that will be used (longer lines will be
    // wrapped).  If 0, no maximum width is enforced.
    void SizeToFit(int max_width);

    // Sets whether the preferred size is empty when the label is not visible.
    void set_collapse_when_hidden(bool value) { collapse_when_hidden_ = value; }

    // Get the text as displayed to the user, respecting the obscured flag.
    base::string16 GetDisplayTextForTesting();

    // View:
    gfx::Insets GetInsets() const override;
    int GetBaseline() const override;
    gfx::Size GetPreferredSize() const override;
    gfx::Size GetMinimumSize() const override;
    int GetHeightForWidth(int w) const override;
    void Layout() override;
    const char* GetClassName() const override;
    View* GetTooltipHandlerForPoint(const gfx::Point& point) override;
    bool CanProcessEventsWithinSubtree() const override;
    void GetAccessibleState(ui::AXViewState* state) override;
    bool GetTooltipText(const gfx::Point& p,
        base::string16* tooltip) const override;
    void OnEnabledChanged() override;

protected:
    // Create a single RenderText instance to actually be painted.
    virtual scoped_ptr<gfx::RenderText> CreateRenderText(
        const base::string16& text,
        gfx::HorizontalAlignment alignment,
        gfx::DirectionalityMode directionality,
        gfx::ElideBehavior elide_behavior);

    void PaintText(gfx::Canvas* canvas);

    SkColor disabled_color() const { return actual_disabled_color_; }

    // View:
    void OnBoundsChanged(const gfx::Rect& previous_bounds) override;
    void VisibilityChanged(View* starting_from, bool is_visible) override;
    void OnPaint(gfx::Canvas* canvas) override;
    void OnDeviceScaleFactorChanged(float device_scale_factor) override;
    void OnNativeThemeChanged(const ui::NativeTheme* theme) override;

private:
    FRIEND_TEST_ALL_PREFIXES(LabelTest, ResetRenderTextData);
    FRIEND_TEST_ALL_PREFIXES(LabelTest, MultilineSupportedRenderText);
    FRIEND_TEST_ALL_PREFIXES(LabelTest, TextChangeWithoutLayout);
    FRIEND_TEST_ALL_PREFIXES(LabelFocusTest, FocusBounds);
    FRIEND_TEST_ALL_PREFIXES(LabelFocusTest, EmptyLabel);

    void Init(const base::string16& text, const gfx::FontList& font_list);

    void ResetLayout();

    // Set up |lines_| to actually be painted.
    void MaybeBuildRenderTextLines();

    gfx::Rect GetFocusBounds();

    // Get the text broken into lines as needed to fit the given |width|.
    std::vector<base::string16> GetLinesForWidth(int width) const;

    // Get the text size for the current layout.
    gfx::Size GetTextSize() const;

    void RecalculateColors();

    // Updates any colors that have not been explicitly set from the theme.
    void UpdateColorsFromTheme(const ui::NativeTheme* theme);

    bool ShouldShowDefaultTooltip() const;

    // An un-elided and single-line RenderText object used for preferred sizing.
    scoped_ptr<gfx::RenderText> render_text_;

    // The RenderText instances used to display elided and multi-line text.
    std::vector<scoped_ptr<gfx::RenderText>> lines_;

    SkColor requested_enabled_color_;
    SkColor actual_enabled_color_;
    SkColor requested_disabled_color_;
    SkColor actual_disabled_color_;
    SkColor background_color_;

    // Set to true once the corresponding setter is invoked.
    bool enabled_color_set_;
    bool disabled_color_set_;
    bool background_color_set_;

    gfx::ElideBehavior elide_behavior_;

    bool subpixel_rendering_enabled_;
    bool auto_color_readability_;
    // TODO(mukai): remove |multi_line_| when all RenderText can render multiline.
    bool multi_line_;
    base::string16 tooltip_text_;
    bool handles_tooltips_;
    // Whether to collapse the label when it's not visible.
    bool collapse_when_hidden_;
    int max_width_;

    // TODO(ckocagil): Remove is_first_paint_text_ before crbug.com/441028 is
    // closed.
    bool is_first_paint_text_;

    DISALLOW_COPY_AND_ASSIGN(Label);
};

} // namespace views

#endif // UI_VIEWS_CONTROLS_LABEL_H_
